Control means for dictation machines



Feb. l, 1944.

A H. K. MANN coNTRoL MEANS Fon DIT'ATION MACHINES v Filed March 31. 1942 mm Ms. mummy WM. H mK um@ A d ,r .M m, QN H hasta! Feb. 1, 1944 CONTROL MEAN B FOR DICTATION MACHINES Hayward K. Mann, South Orange, N. J.. assignor to The Gray Manufacturing Company, Hartford, Conn., a corporation of Connecticut Application March ,31, 1042, Serial No. 436,975 i claims. (o1. 17a-100.4)

'I'his invention relates to improvements particularly concerned with the controlof the amplier and associated parts as employed in a combined sound recording and reproducing machine such for example as a dictation recording and transcribing machine'.A

The subject matter of this application, although not limited to such use, is particularly applicable to a dictation machine of thetype disclosed in the copending application of Barton' A. Proctor and Ferdinand C. W. Thiede, Serial No. 218,082, filed July 8, 1938, now Patent No. 2,296,870, granted September 29, 1942.

A general object of the invention is the provision of a single simply controlled switching device by means of which a plurality of varied interconnections may be established between an amplifier, a microphone, a loudspeaker, a sound recording or cutting head, and a sound reproducing or pick-up head.

A comparable object of this invention and resulting from a combination as referred to above, is to effect simplification in the operation of a dictating machine.

Other and more detailed objects of the invention will be apparent from the following description when taken in connection with the attached drawing.

This invention resides substantially in the combination, construction, arrangement, and relative location of parts as will be described in detail below.

In the accompanying drawing the single figure is a diagrammatic illustration of the elements comprising this invention and their manner of association to secure the objects thereof.

In dictation recording and transcribing machines of some modem types, as for example that disclosed in the above-mentioned application, there is included a multi-stage vacuum tube audio frequency amplifier which serves the purpose of receiving and amplifying the impulses applied thereto by a microphone and supplying those impulses after amplification to the proper magnitude to a sound recording head by means of which representative records thereof are made on suitable record blanks. This amplier is also employed in the same machine during transcription to receive the impulses produced-by the cooperation of a reproducing or pick-up head and the record tablet, and after amplification to supply them to a loudspeaker for recreation as sound waves. This multiple use of the ampliier necessitates suitable switching mechanism which heretofore has been relativelycomplicated and has required special knowledge on the part of the operator in order to effect the proper connections for the various operations of the apparatus. In accordance with this invention all necessary switching operations are actail will be made since, as will become apparent complished by a single instrumentality in' the form of a relay which can be operated by quite simple manipulations on the part of the operator to effect all of the connections necessary to obtain the full operation of the system.

The exact nature of the invention can best be appreciated by describing the mechanism illustrated in the drawing in detail. The refer` ence numeral 5 is employed to indicate the ccmplete multi-stage vacuum tube audio frequency amplifier. No reference to this amplifier in deas the description proceeds, the invention is not concerned specifically with the amplifier, although one suitable form of amplifier has been shown in detail in order to fully understand the relationship of the other parts of the system thereto. The power pack includes a full wave vacuum tube rectifier 3 and associated parts, including a suitable filter network d. The input of the power transformer for the power pack is connected to the terminals I, which input in accordance with common practice may be a 110 volt alternating current light system. The power pack transformer is provided with a secondary which feeds the full wave rectifier and an aux-` iliary secondary which energizes a signal or dial light 6. The negative side of the filter is grounded, as indicated at 2. The common return lead I5 or negative side of the amplifier is grounded as indicated at I4.

The input transformer of the audio frequency amplifier is indicated at Ill. Its primary is associated with the terminal board to which is connected a microphone Il, a loudspeaker I2, and a neon warning light I3. One terminal of g each of these three devices is-connected to the grounded return lead I5. It will be seen that the microphone II is directly connected to the primary of the transformer I 0. The ungrounded side of the loudspeaker is connected by a wire to a xed contact in switch 30 which cooperates with the movable blade 2lib of that switch. The ungrounded terminal of the neon warning light I3 is connected by a wire to one terminal of the relay operating coil 2l, -the other terminal of which is connected to the positive side of the .lter I. The wire from the ungrounded side of the neon light I3 is connectable to ground at 8- through switches 'l and I9. As will be described'w in more detail later, the switch 'I is associated with the mechanism for alternately operating the recording and pick up heads into engagement with the record, and switch I9 is associated with-y the clutch or other driving connection between the main power source and the record tablet. It will be seen from the drawing that when switches 1 and I9' are closed, the neon warning light I3 is short circuited, and is extinguished. but under all other conditions, with either or? Aline in' the gure.

both of switches 1 and I9 open, the warning light I8 is energized. As will be referred toA again later, when switches 1 and I9 are both clcsed the relay winding 2| is energized, operating the switch 20 from the position shown to its other position.

The reproducing head I1 and the recording head I8 are pivotally mounted on the ends of a link 9 which in turn is pivotally mounted at its center on an adjacent part of the machine. The link 9 has an extension and pointer provided with an operating knob 9' positioned in the actual machine for ready access by the operator. When the link 9 is horizontal and the pointer is in neutral or mid position,l both the heads I1 and I8 are out of engagement with the record, the plane of which is indicated by a dash-dot It may be noted that this part of the mechanism is shown in reproducing position, in recording position the pointer will be inclined to the 'right and switch 1 will be closedby it.

Referring again to switch 20, the uppermost movable blade 2|)8L thereof cooperates with the xed contact which is connected to the output transformer I6 of the amplifier. This relay switch also contains a movable blade 20 which normally engages the lower fixed contact, as shown, which is connected to one of the output anodes of an intermediate vacuum tube of the amplifier, as shown. The upper contact associated with this switch blade is connected to the other output anode of the same vacuum tube and to the output anode of the iirst vacuum tube. The cathode switch blade 2i)c is connected to a. point of proper potential in the lter 4 and output transformer IS has its other terminal connected, as shown, to another point in the filter to provide the proper operating potential therefor.

One terminal of the recording head I8 is connected to the movable switch blade 20a. One terminal of the pickup or reproducing head I1 is conncted to the control electrode of the right hand half of the above-mentioned intermediate vacuum tube of the amplier. The other terminals of the recorder I8 and reproducer I1 are connected by a common lead to the grounded side of the lter. Movableswitch blade 2|)b is connected to the ungrounded side of a coil forming part of thev output transformer IB as shown.

There is diagrammatically illustrated herein a part of the mechanism by means of which the power from the drive source (not shown) is applied to the record to rotate it as shown in full detail in the above-mentioned application. This mechanism includes an arm 22 pivotally mounted at 23 and connectable to ground by means of al start-stop switch 30. The free end of the lever 22 is provided with a lroller 24 which engages the top surface of the record when in the depressed position shown in the drawing. When in its raised position the roller 24 is out of contact with the record. As shown in the abovementioned application a power driven roller 24' engages the opposite side of the record in line with the roller 24 so that the record is revolved` when roller 24 is in down position in order to grip the record between it and the power driven roller. The movable contact of switch I9 is mounted on, but insulated from, the lever 22, and is grounded as shown at 8. The xed contact of switch I9 is connected to the fixed contact of switch 1, the movable contact of which is connected to the ungrounded terminal of the relay winding 2|. Switch I9 is open when lever 22 is in the depressed position shown and is closed when the lever is inraised position. The lever 22 is mounted so as to remain in either of the two positions mentioned, when actuated to those positions. This lever is actuated to those positions by means of a pair of magnets 28 and 26. One terminal loi each of these magnets is connected to a grounded current source 21. The other terminal of magnet 25 is connected by wire 29 to a ilxed contact engaged by the lever 22 when depressed. The other terminal of magnet 28 is connected by wire 28 to a fixed contact armged to engage lever 22 when in raised posi- The operation of this system will now be described in detail. When the power for the system is turned on, energy is supplied tothe terminals I and dial light 6 is energized indicating to the operator that the power is on. The parts are shown in the position which they assume when the machine is operating to reproduce and so the description of the operation of the machine will be taken up from this point as being the simplest approach. It will be seen from the ligure that the stylus of the reproducer I] engages the record tablet-which lies in the plane of the dashdot line. The stylus of the recording head I8 is oi the record, switch 1 is open, switch I9 is closed, relay 2| is deenergized, and arm 22 is down so that its roller 24 is gripping the record tablet between it and the lower power driven roller 24'. If the operator desires to stop the machine he simply momentarily closes switch 30, completing a circuit from ground through that switch, lever 22, wire 29, magnet 25, and current source 21 back to ground. Thus magnet 25 is energized, raising arm 22 so that roller 24 disengages the record tablet and it stops rotating. The upper movement of arm 22 opens switch I9 and also causes the engagement of the lever with the contact connected to wire 28. In the meantime, however, switch 30 has opened since the operation of the mechanism requires only momentary closing of switch 30. To again start the machine, the operator merely momentarily closes switch 30, which in this case completes a circuit from ground through that switch, lever 22, wire 28, magnet 26, and current source 21 to ground. The energization of magnet 26 pulls lever 22 down so that the roller 24 engages the record and it again begins to revolve. Throughout the period when the machine is in use, the power driven roller 24 1s rotating continuously. At the end of the reproduction period switch 30 is again momentarily closed to raise lever 22 and link 9 is swung manually to neutral position so that neither the recorder nor the reproducer engages the record.

In order to record, the operator through the agency of knob 9' and the link 9 moves the recorder I8 down so that its stylus engages the record whereupon the reproducer I1 is raised and its stylus disengages the record. At the same time switch 1 is closed, but switch I9 is open, since lever 22 is in raised position. The advantage of this arrangement is that it appears that the worst condition of disturbing electrical feedback occurs if the amplier isconnected when the stylus of the recording head engages the record tablet and the record tablet is stationary.

, However, with this invention the amplifier is not connected to the recorder because switch 20 remains in the position shown by reason of the fact that although switch 1 is closed, switch I 9 is open. In order to record, the operator then momentarily assaeoe closes switch 30 which pulls the lever 22 down to the position shown in the drawing in the manner previously described. At this time, however, the closing of switch i9 completes the circuit to the magnet 2|,.because switch 'l is also closed. Energization of the solenoid '2| shifts switch 20 from the position shown to its other position.- At the same time that winding 2| is energized, the neon warning light I3 is short circuited and extinguished, indicating to the operator that the machine is in recording position. The operation of switch 20 to its other position, as mentioned, causes the breaking of the loudspeaker circuit at switch blade 201 and the making of the recording head circuit at switch blade 20, with the result that the recording head is connected to the output of the amplifier at the transformer I6.

Switch blade 28 disengages its iower contact and engages its upper contact completing the output circuit of the left hand section of the intermediate amplifier tube. The amplier 5 is now operative with the recording head connected to the output thereof and the microphone connected to the input thereof. The record tablet is in motion hence recording may take place. Whenever the dictator interrupts his dictation for any reason and therefore wishes to stop the machine, he momentarily closes switch 30 to raise arm 22 as previously described. Thus the recordv tablet stops and the amplier is disconnected from the recording head because switch I9 opens. Therefore the undesired hum due to feedback cannot occur. Of course every time the motion of the record tablet is stopped the warning light I 3 is energized.

At this point it may be noted that the winding 2| is energized from the power pack of the machine. This is a practical feature of the invention in that the relay winding may be a low Vvoltage winding with the result that thelow voltage direct current neon light I3 may be associated therewith. This light may be mounted directly on the microphone and may have its leads therefore built right into the microphone cable without producing any undesired hum. As soon as the apparatus is energized, as mentioned at the beginning of this description of operation, warning light I3 is energized indicating that tact and the fact that the machine is in reproducing position or in neutral position. However as soon as the machine shifts to a condition where it may record. the warning light is extinguished, indicating to the operator that the machine is in recording condition.

It may be noted as not having been mentioned before that the output of the reproducer I1 during reproduction is fed to the right hand half of the intermediate vacuum tube of the amplier, which in turn feeds the vacuum tube to the right thereof and its output is fed to the loudspeaker through the transformer I6 and switch blade 2lb. Thus during reproduction only the last two tubes of the amplier are used.

From the above description it will be apparent to those skilled in the art 'that the lsubject matter of this invention may be embodied in other physical Iorms, and combinations, and I do not, therefore, desire to be strictly limited tothe disclosure as given for purposes of illustration, but rather to the scope of the claims granted me.

Whatis claimed is:

.1. In a machine of the type described, the combination inc1udinga. multi-stage vacuum .tube ampliiier, a power supply means for said amplifier including a rectifier anda filter.v a microphone 5 connected to the input of said ampler, a loudspeaker, a recording head, a reproducing head, a multiple two-position switch, said switch in its normal position connecting the reproducing head to the input of said amplifier and the loudspeaker l to the output of said amplifier and in'its other position connecting the recording head to the output of said amplifier, and an electro-magnet for operating said switch energized from said power means when the machine is in operation l for recording. y 2. In a machine of the type described, the combination including a multi-stage vacuum tube amplier, a power supply means for said amplier including la rectifier and a filter, a microphone connected to the input of said amplier, a loudspeaker, a recording head. ya reproducing head, a multiple two-position switch, said switch in its normal position connecting the reproducing head to the input of said'amplifler and the loudspeaker to the output of said amplier and` in its other position connecting the recording head to the output of said ampliiier, an electromagnet for operating said switch energized from said power means when the machine is in operation for recording, and a warning light connected with said electro-magnet so as to be deenergized whenever said electro-magnet is energized and to be energized whenever said electromagnet is de-energized.

3. In a machine of the type described, the combination including a multi-stage vacuum tube ampliiier having ilrst and second input terminals and a common output, a microphone connected to the rst o f said input terminals, a recording head, a loudspeaker, a" combination switch having a normal position, circuits including said switch in normal position for connecting said reproducing head to the second of said input terminals and said loudspeaker to said common output, a recording head, circuits including said switch when operated from its v`normal position for connecting said recording head to said common output, and electromagnetic means for operating said switch from its normal to its other the machine in operation.

4. In an electro-acoustic machine Vof the type described, a record support, arecording head, a reproducing head, means for supporting and moving said heads so as to alternatively engage a record when mounted on said support, an'electrical amplier, a loudspeaker. a microphone, circuits including a switch for variously connecting said heads, vspeaker andmicrophone to said amplifier, a magnet for said switch, power means for moving. said support, and a circuit for said magnet including two switches, one of said last switches being closed by, the means for moving said heads when moved to engage the recording head with the record, and the other of said last switches being closed when said power means is operated to cause the record support to move, whereby said magnet is energized to operate the associated switch to connect the microphone to the input of the amplifier.

' HAYWARD KVMANN.

position and energized as an incident to puttingl 

